Blowpipe



Feb. 22, 1938. w. .1. .JAcoBssoN BL OWP I PE Filed Aug. 8, 1334 ATTORNEY Patented Feb. 22, 1938 PATENT OFFICE-A BLowPrPE Wilgot J. Jacobsson, Elizabeth, N. J., assignor, by mesne assignments, to Union Carbide and Carbon Corporation, a corporation of New York Application August 8, 1934, Serial No. 738,925

2 Claims. (Cl. 15S-27.4)

This invention relates to blowpipes and more particularly blowpipes in which a fuel-gas, a combustion-supporting gas, and air' are mixed. The invention relates especially to such blowpipes wherein the proportion of air to one of the other gases with which it is first mixed may l be varied in simple manner.

In the operation of blowpipes it is sometimes desirable to reduce the volume of gas consumed. It may also be desired to supply al1 or a part' of the air'required for combustion within the blowpipe, so that no air need be available about the burner tip. To this end air may be mixed with. either the fuel-gas or the combustion-supportingA gas before the nal mixture is made and before this mixture reaches the ame. In diierent classes of service different ratios of fuel-gas,

combustion-supporting gas and air are required to give greatest operating eiliciency and gas economy. One object of this invention is, therefore,

to provide an apparatus wherein these gas ratios chamber into a mixing throat. Any gas in the chamber will therefore be aspirated into the mixing throat by the stream of gas which is projected through the nozzle. The other gas, that is tol say: either the fuel-gas or the combustionsupporting gas, enters the chamber under a pres'- sure which'may be varied, and an opening of constant section is provided through which at" mospheric air may -enter the chamber. Obviously, the greater the pressure at which the other gas enters the chamber, the greater will be the pressure in the chamber; consequentlyV the slower will be the rate of air ow into the chamber; and therefore the richer will be the mixture of gas and air-in the chamber. Conversely, the lower the pressure at which this other gas enters the chamber, the lower will be the pressure in the chamber; consequently, the-faster will be the air flow into the chamber; and the leaner willbethemixtureofgasandairinthe chamber.' Thus the quality ofthe mixture may be` controlled simply by regulating the' pressure of one'gas.

In the embodiment of the invention illustrated in the drawing there is shown a blowpipe handle I0, having a forward end II, in which the end of a combustion-supporting 'gas conduit I2 and the end of4 a fuel-gas conduit I3 terminate.- As oxygen and acetylene are commonly used as the combustion-supporting gas and the fuel-gas, the conduits I2 and I3 will hereafter be referred to as the "oxygen and acetylene conduits respectively. A duct I4 formed in the forward end Il of the handle connects the oxygen conduit I2 with an oxygen regulating valve I5 from which ducts I6 and I1 in series lead to a chamber I8 at the base of aconcave conical opening I9 in the forward end of the handle. A duct 20 connects the acetylene conduit I3 with an acetylene control valve 2l fro'm which a duct 22 leads to an annular groove 23 in the concave conical opening I9.

A mixing nozzle 24 is secured in operative position Ibetween the handle I0 and a stem 25,

l'the handle, the mixing nozzle and the stem all being held together in 'series relation by a coupling or union 26 which may be screwed upon external threads 21 on the forward end II of. the handle and which, as shown, engages an annular projection 28 on the stem 25 by means of an internal shoulder 29 on the union 2B. A split lring 30 iitting in an annular groove 3| in the stem 25, may bear against a'forward shoulder 32 of the union 26 in order that the stem and-'union may be unscrewed together and held as a unit when detached from the forward end II of the handle.

The nozzle 24 has a convex conical rear end 33 which ilts tightly into the concave conical opening I9 in the forwardend of the handle. An axial bore forms a vcentral passage 34 through the Amixing nomic whose rear end is in open connection with the chamber I8and whose forward end terminates in a nozzle end 35 of vthemixing nozzle. The forward end of the mixing nozzle 24 fits into a cavity in the rear end of the stem 25 and the nozzle end 35 of the mixing vnozzle .is of reducedsection, clearing the wall of the cavity at the rear end of the stem and forming therewitha mixing chamber 36. The stem 25 has an axial bore 31 therethrough, which formsan exit opening to the mixing chamber 36 into which a gas passing through the central passage 34 in 'also forms adjacent the chamber 3G a mixing the mixing nozzle and the handle end. Passages 39 extend through the mixing nozzle from the annular groove 33 to the mix-lng chamber 33, and serve to carry acetylene into the mixing chamber.

The'stem 2l has passages Ill, here shown as.

radial passages, extending from its outer surface into the mixing chamber 36; and the union 26 has a passage extending from atmosphere to the outer ends of the :es lll, the passage in the union being illustrated as an annular recess ll adjacent the outer ends of the radial passages anda plurality of passages 42 connecting the annular recess with atmosphere. The passages 42 extend away 'from the handle so that any dame or gas issuing from them will be projected away from the operator of the blowpipe.

From what has been said, the. operation oi the apparatus 'will be apparent. Oxygen, under control of the oxygen regulating valve I5, passes through the central passage 34' in the mixing nozzle and is projected from the nozzle end 35 through the mixing chamber 38 into the mixing throat 3l. In passing through the mixing chamber 36 the oxygen stream will aspirate any Bas therein into the mixing throat 31, where the oxygen and the aspirated gas will be thoroughly mixed.

At the same time, acetlyene regulated by the acetylene control valve 2i enters the annular .chamber formed between the annular groove 23 andthe annular groove 33 andv passes through the passages 39 to the mixing chamber 36. Atmospheric air also enters Athemixing chamber 36 being drawn through the radial passages I0 by the vacuum produced as the oxygen stream passes through'the mixing chamber. I'he size of the radial passages 40 being constant and thel atmospheric pressure being constant, it will be clear thattheextenttowhichair entersthe mixing chamber 33 will be governed by the pressure of the acetylene entering this chamber. Thus, the acetylene-air mixture may be regulated as to its composition by varying the position ot the acetlyene control valve 2 I.

Clearly, the invention is not limited to the details oi construction and operation here described by wayoi example. Other fuel-gases and other combustion-supporting gases maybe used instead of acetylene and oxygen. Furthermore, the fuel-gas may be passed through the central `passage in the mixing nozzle and 'may' aspirate the combustion-supporting gas which may enter the mixing chamber in the manner which .has been described with respect to 'the supply of acetylene. Other variations and substitutions may also be made without departing from the principles of the invention .and the yproper scope of. the appended claims. y

I claim: l. A blowpipe, for producing flame of varying intensity, comprising a handle; a chamber at the forward end of said handle having inlets i'or acetylene, inlets i'or air, and an outlet constituting a mixing throat, said air inlets being adjacent the entrance to said throat; a nozzle..v

. said oxygen stream.

2. A blowpipe as claimed in claim 1V 1n which the air inlets are directed forwardly `ahead, andl away from the blowpipe handle, whereby-when a flashback occurs, flames issuing from said air inlets will not injure the operator.

wrmo'r J. JAcoBssoN.' 

